1. Field of the Invention
This invention relates generally to a method and apparatus for locking a gooseneck trailer hitch to prevent unauthorized hitching or unhitching of a gooseneck trailer.
2. Description of the Related Art
Although gooseneck trailers have been used for a number of years to haul various types of cargo, a need exists for an acceptable locking mechanism to lock the hitch of a gooseneck trailer to prevent unauthorized hitching or unhitching of the trailer. Few locking devices are known in the art, and the known locking devices are undesirable because they are too cumbersome, complicated, or vulnerable to vandalism. For example, one existing gooseneck trailer hitch locking device comprises a heavy steel box-like structure that fits around the end of the hitch. The top and one end of the box-like structure are open to receive the hitch, and a rod spans the gap between the side walls at the open end to guard against removal of the device after it is installed. The rod is fastened in place with a lock that protrudes from a side wall of the box-like structure. Such device is heavy and cumbersome to install. Additionally, the protruding lock may be sawed off with relative ease or sheared off with a heavy hammer. Those deficiencies severely limit the usefulness of such a device.
Because the existing gooseneck trailer hitch locking devices are so undesirable, many gooseneck trailer owners simply do not lock their trailer hitches. The absence of a lock on a gooseneck trailer hitch presents substantial safety and security problems. During towing operations, a gooseneck trailer hitch may experience large static and dynamic structural loads. Without an effective lock, the trailer hitch may be jolted loose from the hitch ball, which would send the trailer careening down the roadway out of control. Such a runaway trailer could cause severe damage to people and property, including the trailer itself. Additionally, because modern gooseneck trailers may be worth thousands of dollars, the lack of a locking mechanism presents a significant risk of theft for a stationary trailer, particularly for an unhitched trailer. As discussed below, a standard gooseneck trailer hitch provides no means for locking the hitch, either in the hitched or unhitched condition.
FIG. 1 illustrates a top front perspective view of a standard gooseneck coupler 9, such as a Hammerblow™ coupler (U.S. Pat. No. 5,382,109) or equivalent, in a closed position. Coupler 9 comprises a tubular sheathing member 1, which is mountable on a trailer (not shown) by means of a conventional fastening method, such as welding. A stationary plate 5 is fixedly attached to the base of sheathing member 1, and a lock plate 3 is pivotally attached to stationary plate 5, as described below in connection with FIG. 2. Lock plate 3 swings open to allow stationary plate 5 to receive a standard hitch ball 19 into a hitch ball receiving cavity 23 (shown in FIG. 2), the structure and operation of which are well known in the art. Hitch ball 19 is generally attached to a prime mover such as an automobile or truck (not shown). A retainer bracket 4 is fixedly attached to one end of lock plate 3 such that a first flange 26 of stationary plate 5 is disposed within the opening of retainer bracket 4. Retainer bracket 4 thus limits the pivotal range of lock plate 3. A first latch pin aperture 24 is located in the top web 28 of retainer bracket 4 to receive a latch pin 18 of a manually operable handle 2. A spring 6 provides a downward biasing force along the axis of latch pin 18 to resist upward motion of handle 2 away from the first latch pin aperture 24. Spring 6 thus biases handle 2 toward the closed position.
FIG. 2 illustrates a side elevational view of the standard coupler 9 of the prior art in a closed position. A first end of lock plate 3 is pivotally attached via pivot bolt 10 to a second flange 27 of stationary plate 5. A handle guide 11 slidably supports handle 2 such that latch pin 18 is both parallel to sheathing member 1 and mateably aligned with first latch pin aperture 24. A second latch pin aperture 25 is located in first flange 26 of stationary plate 5. Latch pin 18 passes through both the first latch pin aperture 24 and second latch pin aperture 25 to immobilize lock plate 3 in the closed position. A cover plate 7 enshrouds handle guide 11 and spring 6.
FIG. 3 illustrates a partially sectioned top view of the standard coupler 9 of the prior art in a closed position. Lock plate 3 has a hitch ball receiving aperture 30. As is evident, hitch ball receiving aperture 30 is offset relative to the hitch ball receiving cavity 23 of stationary plate 5 when lock plate 3 is in a closed position, which prevents hitch ball 19 (not shown) from being inserted into or removed from the hitch ball receiving cavity 23.
FIG. 4 illustrates a partially sectioned top view of the standard coupler 9 of the prior art in an open position. In this open position, hitch ball receiving aperture 30 is axially aligned with hitch ball receiving cavity 23 such that hitch ball 19 (not shown) may be inserted into or removed from hitch ball receiving cavity 23. Alignment of hitch ball receiving aperture 30 and hitch ball receiving cavity 23 is achieved by manually manipulating handle 2 to slidably remove latch pin 18 from first latch pin aperture 24 and manually pivoting lock plate 3 about the axis of pivot bolt 10.
FIG. 5 illustrates four distinct prior art embodiments of handle 2 (generally depicted) that may be utilized with coupler 9 (not shown). The function of each handle is essentially identical. The structure of each handle, however, may vary according to the preference of the operator. The first of these handle designs is a box chamfer handle 29, the second is a box round handle 20, the third is a box angle handle 21, and the fourth is a pistol grip handle 22. The present invention is not limited to use of any one of these four handle designs. Rather, these designs are illustrative of the various handle configurations that may be used with the present invention. For simplicity, box chamfer handle 29 is depicted in all other Figures and is referred to generically as “handle 2.”
Referring generally to FIGS. 1 through 5, it will be apparent to persons reasonably skilled in the art that the prior art does not provide a suitable means for locking handle 2 in the closed position to prevent unauthorized hitching or unhitching of a gooseneck trailer. Because modern gooseneck trailers may be worth thousands of dollars, the lack of a locking mechanism presents a significant risk of theft. Additionally, due to the large forces that a gooseneck coupler may experience during towing operations, the coupler may become unhitched during travel if it is improperly installed, which presents a serious safety risk. It would, therefore, be a significant advancement in the art to provide a simple way to lock a conventional gooseneck coupler in the closed position to prevent unauthorized hitching or unhitching of a gooseneck trailer.